Level winding winch mechanism and heavy-duty drive therefor

ABSTRACT

A level winding winch mechanism for a suspending staging that includes a frame having an upper portion and a lower portion with a fairlead fixed on the upper portion and a rotatable winch pivotally mounted on the lower portion. The pivot for the winch is below the winch drum axis of rotation. As the wire rope passing through the fairlead approaches an end of the winch drum, that end of the winch drum will be pivoted toward an imaginary vertical perpendicular line between the fairlead and the winch drum. Thus the angle between the wire rope, as it approaches an end of the drum, and the imaginary perpendicular line is kept to a minimum, the effect of which is to maintain the &#39;&#39;&#39;&#39;fleet angle&#39;&#39;&#39;&#39; at approximately 90* . Also the pivot is remotely spaced from the winch drum axis of rotation to reduce the angle through which the winch drum must pivot and thus allow the use of winch drums of long lengths which would otherwise strike the frame of the staging when pivoted. A pivot control using a primary spring and a secondary spring energized only after the wire rope reaches a predetermined point on the winch drum is provided to counteract the increase in leverage when an extra long winch drum is used. A low temperature-high capacity drive arrangement for a winch on a suspended staging. A pair of worms are driven through spur gears from a common pinion spur gear on a motor shaft. The worms engage two worm gears fixed on a common shaft. A beveled pinion gear is also fixed to an end of the worm gear. The beveled pinion gear meshes with a beveled ring gear which is secured to the winch drum. The distribution of the loading between the worms reduces the operating temperature of the drive arrangement for compliance with the rigid safety requirements for suspended staging. Oil from the worms is splashed against a vertical fin extending down from the top of the worm gear casing. The fin guides the oil into a trough through the walls between the spur and worm gear casing for lubricating the driven spur gears.

United States Patent Brauss Sept. 12, 1972 1 LEVEL WINDING WINCHMECHANISM AND HEAVY-DUTY DRIVE THEREFOR [72] Inventor: Albert Brauss,Redmond, Wash.

[73] Assignee: Spider Staging, Inc., Seattle, Wash.

221 Filed: Oct-21, 1968 211 Appl. No.: 769,326

[52] US. Cl. ..l82/142, 187/27, 254/186, 267/60 [51] Int. Cl ..E04g l/l8[58] Field of Search...l87/20, 27; 182/142; 242/158; 262/60, 168;254/187, 186

[56] References Cited UNITED STATES PATENTS 2,998,094 8/1961 Fisher..182/l42 3,297,312 l/l967 Hines ..267/60 Primary Examiner-Harvey C.I-lornsby Attorney-Graybeal, Cole & Barnard 57 ABSTRACT through thefairlead approaches an end of the winch drum, that end of the winch drumwill be pivoted toward an imaginary vertical perpendicular line betweenthe fairlead and the winch drum. Thus the angle between the wire rope,as it approaches an end of the drum, and the imaginary perpendicularline is kept to a minimum, the effect of which is to maintain the fleetangle at approximately 90. Also the pivot is remotely spaced from thewinch drum axis of rotation to reduce the angle through which the winchdrum must pivot and thus allow the use of winch drums of long lengthswhich would otherwise strike the frame of the staging when pivoted.

A pivot control using a primary spring and a secondary spring energizedonly after the wire rope reaches a predetermined point on the winch drumis provided to counteract the increase in leverage when an extra longwinch drum is used.

A low temperature-high capacity drive arrangement for a winch on asuspended staging. A pair of worms are driven through spur gears from acommon pinion spur gear on a motor shaft. The worms engage two wormgears fixed on a common shaft. A beveled pinion gear is also fixed to anend of the worm gear. The beveled pinion gear meshes with a beveled ringgear which is secured to the winch drum. The distribution of the loadingbetween the worms reduces the operating temperature of the drivearrangement for compliance with the rigid safety requirements forsuspended staging. Oil from the worms is splashed against a vertical finextending down from the top of the worm gear casing. The fin guides theoil into a trough through the walls between the spur and worm gearcasing for lubricating the driven spur gears.

7 Claims, 7 Drawing Figures PATENTEDsEP 12 me SHEET .3 [1F 3 WMQWALLEVEL WINDING WINCH MECHANISM AND HEAVY-DUTY DRIVE THEREFOR BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention pertains towinch mechanisms and more particularly relates to an improved levelwinding winch mechanism for exceptionally long winch drums on asuspended staging and to a drive unit for rotating the winch drum.

2. Description of the Prior Art Heretofore one type of winch mechanismfor suspended staging has employed a pivot point which is located abovethe axis of rotation of the winch drum and about which the winch maypivot. This arrangement has performed satisfactorily for nominal sizedwinch drums, that is, drums not exceeding about 16 inches in length andhaving a capacity of approximately 1,000 feet of /16 inch diameter wirerope, for example. Such a pivot arrangement is disclosed in the U.S.Pat. to Fisher No. 2,998,094, issued Aug. 29, I961.

With the increasingly higher elevations of modern buildings, for whichthe suspended staging is used, it is necessary to increase the wire ropecarrying capacity of the winch drums. The capacity is increased in partby lengthening the drum to about 21 inches. Increasing the capacity ofthe'winch drum by increasing its length presents two serious problems:(1) The angle with which the wire rope meets the surface of the drum(fleet angle) as the wire rope approaches an end of the drum becomessmaller, that is, varies from the optimum approach angle of 90, and as aresult increases the possibility of non-uniform winding of the wire ropeon the drum. (2) When using an extra long winch drum the wire rope actsthrough a longer lever arm and exaggerates floppingf of the drum aboutits pivot. In addition, high modern buildings call for increased runningtime and heavier suspended platforms and make desirable transmissions ofgreater load capacity at increased speed. I

The angle of approach of the wire rope with respect to the surface ofthe drum is commonly called the fleet angle". As is explained in moredetail in the aforesaid Fisher patent, the'fleet angle is optimumally 90to the drum surface as, for example, in the condition when the wire ropeis directly beneath the fairlead of the staging frame.

SUMMARY OF THE INVENTION This invention is directed to overcoming theaforementioned problems encountered with increased capacity and lengthof the winch drum. As to the first problem, the fleet angle is keptclose to 90, by shifting the ends of the drum axially while the cable isbeing wound or unwound. Preferably shifting is obtained by pivoting thewinch about a pivot point located below the axis of rotation of thewinch drum. Then, with reference to an imaginary vertical perpendicularline through the fairlead which corresponds to a fleet angle of 90, theend of the drum which the wire rope is approaching is pivoted or shiftedtoward said imaginary perpendicular line to decrease the angle betweenthe wire rope and the imaginary perpendicular line and thus to increasethe fleet angle of the wire rope and the surface of the drum. Theproblem is additionally compensated for by placing the pivot point at amore remote distance from the drum axis of rotation.

To alleviate the second problem, a pivot control mechanism is providedto apply a variable resistance in opposition to the pivotal action ofthe winch to counteract the increase in lever arm as the wire ropeapproaches the end of an extra long drum. A primary resistance iscontinually increased until the wire rope reaches a predetermined pointalong the length of the drum, for example, three-fourths of the distanceacross the length of the drum, and then a constantly increasingsecondary resistance is added to the primary resistance to counteractthe increased leverage. The pivot control prevents flopping of the drumabout the pivot as the wire rope is wound or unwound from the drum.

The problem of increased load is overcome by using a double worm drivewith each worm sharing in the load distribution. In addition, a uniqueoil distribution arrangement is provided which transfers oil onto a finin the top wall of the worm gear housing where it flows into the spurgear housing and is distributed onto the spur gears.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view from alower aspect of a single-suspension power driven staging, incorporatinga high capacity winch unit characterizing the present invention;

FIG. 2 is a side view of a portion of the equipment illustrated in FIG.1 with parts broken away for clarity;

FIG. 3 is a fragmentary section of a tilt control assembly incorporatedin the equipment illustrated in FIG. 2;

FIG. 4 is a fragmentary plan view of the equipment illustrated in FIG.1;

FIG. 5 is a cross'sectional view of a portion of the drive unit used inthe equipment shown in FIG. 1, taken along the line 5-5 of FIG. 4 andwith parts broken away for clarity;

FIG. 6 is an end elevation of the equipment shown in FIG. 5 and partlyin cross-section as taken along the line 6-6 of FIG. 5;

FIG. 7 is an elevation view of the drive unit partly in section as takenalong the line 7-7 of FIG. 6 and with parts broken away for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With respect to a generaldescription of the staging equipment incorporating a preferredembodiment of the invention, the staging comprises a frame 10 having anupper portion 12 and a lower portion 14. The upper portion includes anoperators cage C having a deck D and mounting a fixed mast or tripod Thaving at the top thereof a wire rope guide or fairlead F. Wire rope Ris led through the fairlead from a mounting on top of the building fromwhich the staging is suspended. A winch unit W is mounted below the deckD in the lower portion of the frame and includes a power driven winchdrum WD around which the wire rope is wound.

As is readily understood and as described in the aforesaid Fisher U.S.Pat. No. 2,998,094, this type of equipment is operator controlled and isdesigned to be suspended from a single wire rope along the side of abuilding, antenna structure, stack or the like. The

operator selectively can control up and down movement of the stagingwhile riding in the cage C by means of an electric control panel P. Itis important on this type of equipment, where safety and reliability ofoperation are required, that the wire rope R be wound onto and from thewinch drum WD evenly and smoothly.

With reference to FIG. 1 the staging details are in many respects quitesimilar to those of the staging disclosed in the aforesaid Fisher U.S.Pat. No. 2,998,094 with the upper portion 12 of the frame 10 serving tosupport the operator and the tripod T providing a support for thefairlead F. The fairlead in the instant application includes threecase-hardened pins, not shown, that guide the wire rope as it passesthrough the tripod. A tension holder 17 is fixed to the tripod justbelow the fairlead and includes two sets of vertically spaced rollersI8, 20. The wire rope R passes between the sets of rollers and one setis movable toward the other by a handle 21 to hold the wire rope andkeep it from forming loose coils on the drum when the staging platformis rested on the ground. When the handle is released the rollers serveas additional low friction guides to position and reduce wear on thewire rope R.

As is best shown in FIGS. 1 and 2, the lower portion 14 of the stagingframe I is provided with a rectangular bottom frame 22 which includespairs of spaced lower and upper cross braces 24 and 25, respectively.Each of the four cross braces is provided with a support plate 26 whichmount two vertical braces 27 joining the lower and upper cross braces.An I-beam 28 is secured between each support plate 26 and vertical brace27. As shown in FIG. 1 the I-beam is provided with two sets ofvertically downwardly extending pin-mounting brackets 30 which areapertured to receive a pivot pin 32. Thus, two pivot pins are providedat spaced distances along the I-beam 28. Mounted for free pivotalmovement on each pivot pin is a pivot block 34 that is formed integrallyon each of two sets of webs or arms 36. The webs are spaced from oneanother to provide a central opening 38 which surrounds the I-beam 28and are secured at their upper ends to a winch mounting plate 40. Asupport block 41 mounts a right hand, as viewed in FIG. 2, bearing block42 and is fixed, as by welding, to the winch mounting plate. A left handbearing block 44 is fixed to the other end of the winch mounting plate.The bearing blocks rotatably mount an axle 46 on which the winch drum WDis rigidly secured. An electric motor M and suitable driving gear, to belater described, are also secured to the winch mounting plate 40 forrotating the winch drum. The motor M is a suitable reversible electricmotor or, in the alternative, may be an air motor or an internalcombustion engine as disclosed in the aforesaid Fisher US. Pat. No.2,998,094. The motor and drive gearing are suitable to rotate the winchdrum at the desired speed to provide a vertical staging climbing rate ofapproximately 18 feet per minute. l-Iigher or lower speeds may, ofcourse, also be obtained depending on the safety requirements and thetype of service to which the staging is being employed.

As the wire rope R winds from end to end on the winch drum WD the drumwill tend to flop or rock on the pivot pins 32 each time the wire rope Rpasses the vertical center line of the pivot pins. A tilt controlassembly 50 is provided to dampen the intensity of this rocking action.As is best shown in FIGS. 2 and 3 the tilt control assembly 50 includesa cylinder 51 that is pivotally secured to the bottom frame 22. Acontrol rod 52 is slidably received in a stepped-diameter abutment tube53. A small collar or stop tube 53a of a soft metal, such as aluminum,is positioned on the control rod 52 at one end of the abutment tube 52and serves as a positive stop to limit the pivotal movement of the winchunit W in one direction. The tilting of the winch unit W in the otherdirection is limited to a lesser degree by washer 59 resting on a tube58 that is fixed to the cylinder 51. This is to compensate for theeffect of the lay of the wire rope which is discussed later. Theabutment tube 53 has an enlarged portion 53b that acts as a springabutment for a secondary spring 54. A primary spring 55 circumscribesthe control rod and abutment tube and engages a pair of spaced upper andlower washers 56a and 56b, respectively, secured to the control rod byadjustable nuts 57. The washers each engage a clip ring 58 secured ingrooves in the ends of the cylinder 51. The free end of the control rod52 is pinned for pivotal movement to the support block 41 on theright-hand end of the winch mounting plate 40. As may be readily seen inFIG. 2, pivotal movement of the winch unit w to the left about the pivotpins 32 will pull the control rod 52 against the lower washer 56b tocompress the primary spring 55 against the upper washer 56a. As thewinch unit continues to pivot toward the left the secondary spring 54engages the upper washer 56a and is compressed against the enlargedportion 53b of the abutment tube 53. The secondary spring 54 engages theupper washer 56a only after the primary spring has undergoneconsiderable compression and thus acts to immediately increase theresistance against further pivotal movement of the winch unit. Thisfeature is important since the extra long length of the drum WD causesthe wire rope R to move further out from the pivot point (pivot pins 32)of the winch unit and this substantially increases the lever arm andtorque acting to pivot the winch unit. As the lever arm increases thesecondary spring becomes engaged to counteract the increased torque andthus keeps the pivotal movement under control in all position. The stoptube or collar 53a engages the upper washer 56a when the unit haspivoted the maximum limit desired and prevents further pivoting in thatdirection. The stop tube may be easily replaced with a stop tube of alarger or smaller length to vary the pivotal limits.

Pivot movement of the winch unit W to the right, as viewed in FIG. 2, isalso controlled. Pivotal movement in this direction will first compressthe primary spring 55 between the upper and lower washers 56a and 56band then will compress the secondary spring 54 as the pivotal movementcontinues. Finally the washer 59 will engage the tube 58 to prohibitfurther movement.

The pivotal movement of the winch drum WD with respect to the fairlead Fis best shown in FIG. 2. In FIG.

2 an imaginary, vertical perpendicular line x has been drawn downwardfrom the fairlead F to a horizontal plane y that passes through thecenter line or axis of rotation of the winch drum WD when the winch drumis in the horizontal position. With the drum horizontal the imaginaryperpendicular line x and the plane y are at right angles with the wirerope as shown in FIG. 2

being vertically beneath the fairlead. The wire rope actually engagesthe drum or previously made coils on the drum on a tangent at plane yand-thus the fairlead is not directly above the drum. For the purpose ofdescribing this invention, however, the angles discussed will be withreference to FIG. 2 it being assumed that the location of the fairleadwith respect to the tangency of the rope on the drum may vary somewhatwithout affecting the operation of the device. It should also be notedthat the fairlead is not over the center of the drum as viewed in FIG.2. This is due to the fact that the lay of the individual strands ofwire rope causes the wire rope to slip more easily when approaching oneend of the drum than the other. It is for this reason that the movementof the winch unit W to the right is smaller than to the left which isaccomplished by letting washer 59 contact tube 58. In the embodimentshown, for example, the right-hand end of the winch drum is spaced afurther distance from fairlead and the imaginary perpendicular line xthan the other. As shown in phantom lines in FIG. 2 the wire rope,indicated by phantom line R, has reached the right-hand end of the winchdrum WD and in so doing has caused the winch unit W to pivot aboutthe'pivot pins 32. As is readily seen the right-hand end of the winchdrum has shifted to the left toward the imaginary perpendicular line x.Thus the angle between the imaginary perpendicular line x and the wirerope R in the phantom position is less than if the drum had been fixed.This, of course, causes the angle between the wire rope and the plane y,i.e., the fleet angle", to more closely approach the 90 right angle thatis considered most desirable for winding the wire rope onto the winchdrum.

It should be noted that other means for shifting the ends of the winchdrum, such as a rack and pinion or the cam-type pivot shown in theFisher US. Pat. No. 2,998,094, may also be used.

The pivot point of the drum WD in the preferred embodiment isapproximately 18% inches below the axis of rotation of the drum. Thelength of the drum is 21 inches and the distance of its axis below thedeck D and fairlead F are respectively about 8% and 70 inches.

In reaching the position indicated by the phantom line R at the end ofthe winch drum WD it can be seen that the lever arm, that is, the axialdistance along the drum between the pivot pins 32 and the point at whichthe wire rope is wound on the drum, has steadily increased. As theelectric motor M applies a constant tension on the wire rope theincrease in this lever arm tend to increase the torque of the winch unitabout the pivot point or pins 32. When the wire rope reaches theapproximate location indicated by the reference character 70, which mayvary to some degree, the secondary spring 54 in the tilt controlassembly 50 comes in to play and provides an additional constantlyincreasing resistance to overcome and balance this increase in torque.Consequently a smooth pivotal movement of the winch unit about the pins32 is maintained and flopping is eliminated.

The driving arrangement that permits distribution of the loading andimproved oil lubrication for the enlarged, high capacity type winch unitW on the staging described is best shown in FIGS. 4-7. A drive unitincludes three interconnected housings, namely, a spur gear housing 76,a worm gear housing 78 and a ring gear housing 80. As best shown in FIG.7 a common vertical wall 82 interconnects the spur gear housing and theworm gear housing. A top wall 84, (FIG. 6), covers the worm gear housingand is provided with an oil transfer blade or fin 86, for a purpose tobe later described, that terminates above a hollow tube 87 mounted inthe common vertical wall 82 and passing into the spur gear housing. Thetube 87 is cutaway to form a trough to catch the oil flowing from thefin 86.

The motor M is bolted to the spur gear housing 76 and includes an outputshaft 90 having a spur pinion gear 91 keyed thereto. The pinion gear 91drives a pair of spaced spur gears 92 which are keyed to a pair ofrotatably mounted worm shafts 94. Each worm shaft includes a worm 96which meshes with a worm gear 97 fixed on a common shaft 98. The commonshaft is rotatably mounted in suitable hearings in the end walls of theworm gear housing 78. One end of the common shaft 98 extends into thering gear housing 80 and has keyed to its free end a suitable bevelpinion 102. The bevel'pinion meshes with a bevel ring gear 104 that iskeyed to the axle 46 of the winch drum WD. As is readily seen theloading of the worm gears is distributed between the two worms 96. Thusthe dual worm gears reduce the tangential pressure and sliding frictionbetween the worm gears and the worms to produce a substantial reductionin temperature rise and an increase in load capacity.

Oil dippers 110, made of any suitable material, such as synthetic, oilresistant rubber, include a plurality of peripherally spaced cups 112which dip into an oil reservoir 114, common to the spur and worm gearhousings 76 and 78, and fling the oil onto the worms 96. The oil dippersare a supplementary lubricating feature and assist in oil distribution.

As is best shown in FIG. 6, the reservoir 114 is at the same level ineach housing due to free flow through a port 116 in the common wall 82.The worm gears 97 and spur pinion gear 91 are lubricated by dipping intothe reservoir and one worm and one spur gear are lubricated by directtransfer of the oil from the respective worm gear or spur pinion gear.For example, if the spur pinion gear is rotating clockwise, as viewed inFIG. 5, the left-hand spur gear will receive most of the oil carriedfrom the reservoir 114 by the pinion. The righthand spur gear islubricated by oil passing through the tube 87 that flows onto the pinion91 and thus directly onto the right-hand spur gear. An additionalreservoir 120 is provided in the ring gear housing to lubricate the ringgear 104 and the beveled pinion gear 102. As is thus readily apparentall parts of the driving gearing are effectively lubricated at alltimes. To still further increase cooling the worm gear housing 78 isprovided with a plurality of fins 122 that dissipate heat generated intothe surrounding ambient air.

It will be readily apparent that the motive power may be varied withouteffecting the principles of the invention. Likewise, it is of course tobe kept in mind that the tolerable fleet angle variation in a specificinstallation depends to some extent on the nature of the cable or wirerope being used and the lay or wrap of the wire rope. It is well knownthat a given wire rope, for example, has a characteristic greater orlesser tendency to bunch or gap (slip) than other similar wire ropes anddemands correspondingly greater or lesser control of fleet anglevariation. Further, it is also well known that a given tendency to bunchor gap often exerts itself to a greater extent at one end of the winchdrum more than at the other end, and it would be readily understood thatthe degree of compensation for the fleet angle variation contemplated bythe present invention can be adjusted to maximize compensation wheremost needed. I

Having consider in detail the specific construction and operation of apreferred embodiment of the invention, various other modificationsthereof will readily occur to those skilled in the art, within thespirit and scope of the following claims.

What is claimed is:

l. A winch mechanism for a suspended, power driven staging, comprising:

a staging frame having upper and lower portions;

an elongate winch drum mounted on said frame and having spaced ends anda central rotation axis between aid ends;

a fairlead fixed to said staging frame upper portion and positionedalong an imaginary vertical line extending perpendicularly of said winchdrum axis of rotation when in a horizontal position;

flexible rope means coiled around said winch drum;

means mounting said winch drum for rotation about said rotation axis;

movable means supporting said winch drum mounting means for enablingmovement of a winch drum end towards said imaginary vertical line assaid rope means coils toward said winch drum end; said movablesupporting means comprising pivot means spaced below said winch drumaxis of rotation; and a stop means for limiting said winch drum endmovement toward said imaginary vertical line after a. predeterminedamount of movement is obtained. 2. The winch mechanism defined by claim1 further including a control assembly for resisting movement of I saiddrum end toward said imaginary vertical line.

3. The winch mechanism defined by claim 1 further including a controlassembly for resisting tilting movement of said drum.

4. The winch mechanism definedby claim 3 wherein said control assemblyincludes primary resistance means for applying a constantly increasingforce and secondary resistance means. operable when said drum rotationaxis exceeds a predetermined angle.

5. The winch mechanism defined by claim 4 wherein said primary andsecondary resistance means are compression springs.

6. The winch mechanism defined by claim 1 wherein the distance betweensaid pivot means and said winch drum is greater than the half-length ofsaid winch drum.

7. The winch mechanism defined byclaim 6 wherein said winch drumhalf-length is about 10.5 inches and said distance between said pivotmeans and said axis of rotation is about 18.5 inches.

1. A winch mechanism for a suspended, power driven staging, comprising:a staging frame having upper and lower portions; an elongate winch drummounted on said frame and having spaced ends and a central rotation axisbetween aid ends; a fairlead fixed to said staging frame upper portionand positioned along an imaginary vertical line extendingperpEndicularly of said winch drum axis of rotation when in a horizontalposition; flexible rope means coiled around said winch drum; meansmounting said winch drum for rotation about said rotation axis; movablemeans supporting said winch drum mounting means for enabling movement ofa winch drum end towards said imaginary vertical line as said rope meanscoils toward said winch drum end; said movable supporting meanscomprising pivot means spaced below said winch drum axis of rotation;and stop means for limiting said winch drum end movement toward saidimaginary vertical line after a predetermined amount of movement isobtained.
 2. The winch mechanism defined by claim 1 further including acontrol assembly for resisting movement of said drum end toward saidimaginary vertical line.
 3. The winch mechanism defined by claim 1further including a control assembly for resisting tilting movement ofsaid drum.
 4. The winch mechanism defined by claim 3 wherein saidcontrol assembly includes primary resistance means for applying aconstantly increasing force and secondary resistance means operable whensaid drum rotation axis exceeds a predetermined angle.
 5. The winchmechanism defined by claim 4 wherein said primary and secondaryresistance means are compression springs.
 6. The winch mechanism definedby claim 1 wherein the distance between said pivot means and said winchdrum is greater than the half-length of said winch drum.
 7. The winchmechanism defined by claim 6 wherein said winch drum half-length isabout 10.5 inches and said distance between said pivot means and saidaxis of rotation is about 18.5 inches.